The OCL3 promoter from Sorghum bicolor directs gene expression to abscission and nutrient-transfer zones at the bases of floral organs
| Autor: | Zhengxiang Ge, Thomas E. Clemente, Dominique J. Roche, John G. Carman, K. K. Dwivedi |
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| Rok vydání: | 2014 |
| Předmět: |
Base Sequence
biology fungi Sequence Homology food and beverages Chalaza Original Articles Flowers Plant Science Plants Genetically Modified biology.organism_classification Floral organ abscission Polymerase Chain Reaction Endosperm Abscission Fruit abscission Gene Expression Regulation Plant Botany Arabidopsis thaliana Cloning Molecular Silique Promoter Regions Genetic Ovule Sorghum Plant Proteins |
| Zdroj: | Annals of Botany. 114:489-498 |
| ISSN: | 1095-8290 0305-7364 |
| Popis: | †BackgroundandAims During seed fill in cereals, nutrients are symplasmically unloaded to vascular parenchyma in ovules, but thereafter nutrient transport is less certain. In Zea mays, two mechanisms of nutrient passage through the chalaza and nucellus have been hypothesized, apoplasmic and symplasmic. In a recent study, nutrients first passed non-selectively to the chalazal apoplasm and were then selectively absorbed by the nucellus before being released to the endosperm apoplasm. This study reports that the promoter of OUTER CELL LAYER3 (PSbOCL3 )f romSorghum bicolor (sorghum) directs gene expression to chalazal cells where the apoplasmic barrier is thought to form. The aims were to elucidate PSbOCL3 expression patterns in sorghum and relate them to processes of nutrient pathway development in kernels and to recognized functions of the homeodomain-leucine zipper (HD-Zip) IV transcription factor family to which the promoter belongs. †Methods PSbOCL3 was cloned and transformed into sorghum as a promoter‐GUS (b-glucuronidase) construct. Plant tissues from control and transformed plants were then stained for GUS, and kernels were cleared and characterized using differential interference contrast microscopy. †KeyResults A symplasmic disconnect between the chalaza and nucellus during seed fill is inferred by the combination of two phenomena: differentiation of a distinct nucellar epidermis adjacent to the chalaza, and lysis of GUSstained chalazal cells immediately proximal to the nucellar epidermis. Compression of the GUS-stained chalazal cells during kernel maturation produced the kernel abscission zone (closing layer). †Conclusions The results suggest that the HD-Zip IV transcription factor SbOCL3 regulates kernel nutrition and abscission. The latter is consistent with evidence that members of this transcription factor group regulate silique abscission and dehiscence in Arabidopsis thaliana. Collectively, the findings suggest that processes of floral organ abscission are conserved among angiosperms and may in some respects differ from processes of leaf abscission. |
| Databáze: | OpenAIRE |
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